Hydrometallurgical process for the recovery of copper, lead or zinc

Abstract

A hydrometallurgical process for the treatment of polymetallic ores and sulphide concentrates of copper and zinc, and by-products of lead and zinc from smelting plants, treated independently and / or as mixtures thereof, which contain relevant amounts of lead, copper, zinc, iron, gold and silver, such as the matte-speiss mixture of lead foundries, and copper cements from the purification processes of electrolytic zinc plants. Thee process allows the recovery of metallic copper, zinc, copper as copper and zinc basic salts, which may be hydroxides, carbonates, hidroxysulphates or mixtures thereof; the production of stable arsenic residues; and the effective and efficient recovery of Pb, Au and Ag as a concentrate of lead sulphide and / or lead, Au, and Ag sulphate.

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention relates to hydrometallurgical processes for the recovery of Cu, Pb and / or Zn from polymetallic minerals and sulphide concentrates, and by-products from lead smelting plants such as the matte-speiss mixture, with relevant valuables of gold and silver, and copper cements from the purification processes of electrolytic zinc plants, in particular, the process allows the recovery of the metals copper and zinc, such as copper and zinc basic salts, which can be hydroxides, carbonates, hydroxysulphates or mixtures thereof; the production of stable arsenic residues; and the effective and efficient recovery of Pb, Au and Ag as a concentrate of lead sulphide and / or lead, Au, and Ag sulphate.BACKGROUND OF THE INVENTION[0002]For more than two decades, renewed interest has emerged in the development of hydrometallurgical process technologies. The impetus of these developments is mainly due to the desire to develop a viable alternative fo...

AI Technical Summary

Benefits of technology

The present invention provides a hydrometallurgical process that can recover metallic copper and zinc in the form of salts, such as hydroxides, carbonates, hydroxysulphates or mixtures thereof. Additionally, the process can produce stable arsenical waste. It can also effectively and efficiently recover concentrates of lead sulphide, lead, silver and gold.

Problems solved by technology

The recovery of noble metals from leaching residues containing sulphur is much more difficult.

Particularly, when there is jarosite formation, gold recovery from total residues of oxidative leaching by cyanidation is high, but silver recovery is limited by silver jarosite formation.

A major difficulty is the recovery of noble metals from leaching residues containing S° because this involves drying the residue, removing the S° with an organic solvent, and performing pressurised leaching followed by cyanidation.

However, capital costs and plant maintenance are relatively high because chloride solutions require special construction materials and, additionally, electrowinning directly from solutions of chlorides does not produce copper cathodes which is the accepted form of copper for sale.

Silver can be recovered via cementation with copper, but gold recovery is difficult with direct cyanidation due to the S°.

Pyrite is generally not significantly leached, meaning that the gold cannot be recovered if it is associated with the pyrite.

Despite the various developments in recent decades on the hydrometallurgical copper processes, there is still no operable commercial process for treating chalcopyrite concentrates, primarily because (1) the power requirements for leaching and electrowinning sulphates are higher than for modern smelting and electrorefining processes; (2) capital and operating costs are not well defined and are based on preliminary estimates that tend to underestimate the actual costs, therefore there are no commercial operations; (3) the technical risk for the development of any new process is very high; (4) the recovery of noble metals, especially silver from leaching residues, is difficult and recoveries are uncertain, especially from waste containing sulphur, and (5) the disposal of leaching waste is the main problem which limits hydrometallurgical processes in more remote areas.

In all cases where leaching is assisted by chlorides, the special materials used in the leaching process increase the capital costs.

One disadvantage of the method claimed in this patent is a that the hydrometallurgical treatment is assisted by chlorides and chlorides used at small scales may be manageable but at larger scales handling chlorides becomes expensive due to maintenance requirements.

Capital and plant maintenance costs are relatively high because chloride solutions require special construction materials.

Work at high pressure (1000 kPa) also means higher capital costs.

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